Optical modules are continually being redesigned to deliver higher bandwidth densities with reduced power consumption and assembly costs. As an example, there is a need for optical modules that use a photonics device and are capable of carrying large amounts of data. High bandwidth optical modules are a key to solving ever increasing data traffic problems in data center systems for board to board and chip to chip applications.
Conventional packaging architectures usually require multi-die systems that typically require at least three package configurations. One package configuration includes stacked dice where there is direct attachment of a transmitter integrated circuit (hereafter IC) that includes a distributed driver directly attached to a silicon photonics transmitter die. Another package configuration typically includes a receiver IC closely located with a photo-detecting receiver IC. Still another package configuration commonly includes a power management IC that is attached to a package substrate (e.g., by flip chip attachment).
There are usually optical components on the silicon photonics transmitter and the photo-detecting receiver IC. As an example, there may be passive alignment between fiber arrays to the optical I/O areas the silicon photonics transmitter and the photo-detecting receiver IC. These optical I/O areas on the silicon photonics transmitter and the photo-detecting receiver IC typically overhang from the substrate where the silicon photonics transmitter and the photo-detecting receiver IC are mounted.
One of the drawbacks with conventional optical modules is that there are fine pitch flip chip interconnect areas for high density die stacking and higher RF performance, especially between the transmitter IC and the silicon photonics transmitter die as well as mounting photo-detecting receiver IC and the receiver IC to the substrate. Normally, the silicon photonics transmitter and the power management IC are attached to the substrate with large bump interconnect pitch in contrast to the fine pitch interconnect (e.g., 80 um pitch) that is used connect photo-detecting receiver IC and the receiver IC to the substrate. These differences between the size of the interconnects for the various components as well as the use of fine pitch interconnects generally make it difficult to have high assembly yield, robust reliability and good signal integrity for the components that form conventional optical modules.